Pump or motor device



Nov. 28, 1961 P. M. TOMELL,

PUMP 0R MOTOR DEVICE 2 Sheets-Sheet 1 Filed March 19 1959 Nov. 28, 1961 Filed March 19, 1959 P. M. TOMELL PUMP OR MOTOR DEVICE 2 Sheets-Sheet 2 INVENTOR.

United States Patent 3,010,405 PUMP 0R MOTOR DEVICE Paul M. Tomell, Aurora, 11]., assignor to Sundstrand Corporation, a corporation of Illinois Filed Mar. 19, 1959, Ser. No. 800,483 10 Claims. (Cl. 103161) This invention relates to hydraulic pump or motor devices, and more particularly to a radial piston pump.

It is a general object of the invention to provide a new and improved radial piston pump or motor device.

A more specific object is to provide a radial piston pump having a new and improved eccentric for actuating the pump pistons.

Another object is to provide a new and improved radial piston pump having two axially spaced banks or rows of radial pump pistons and cylinders in an axially movable cylinder block, a single axially movable eccentric for actuating the pistons, and a pair of oppositely inclined surfaces on the inner periphery of the eccentric engageable respectively by the pistons of the two banks of pistons to maintain the eccentric properly centered between the two banks of pistons.

Other objects and advantages will become readily apparent from the following detailed description taken in connection with the accompanying drawings, in which:

FIG. 1 is a front elevational view of a pump embodying the principles of the present invention;

7 FIG. 2 is a vertical transverse sectional view taken at about the line 22 of FIG. .1;

FIG. 3 is a horizontal longitudinal sectional view taken at about the line F3 of FIGS. 1 and 2;

FIG. 4 is a vertical longitudinal sectional view taken at about the line 44 of FIGS. 2 and 3;

FIG. 5 is a fragmentary sectional view taken at about the line 55 of FIG. 3;

FIG. 6 is an enlarged fragmentary sectional View similar to FIG. 4, illustrating the cooperation between the outer piston ends and the inner'eccentric surfaces; and

FIG. 7 isa view, similar to FIG; 6, showing the parts in another position. 1 While an illustrative embodiment of the invention is shown in the drawings andwill be described in detail herein, the invention is susceptible of embodiment in manydifferent forms, and it should be understood that the present disclosure is to be considered as an exemplification of the principles of the invention and is not-intended to limit the invention to the embodiment illus trated. The scope of the invention will be pointed out in the appended claims.

Referring now to the drawings in more detail, as illustrated, the invention is embodied in a pump including a housing comprised of a pair of complementary housing members 10 and 11 adapted to be secured firmly together as by screws illustrated at 12. The interior of the housing members Blend 11 is hollow and provides an internal cavity 14 for receiving the operating parts of the pump mechanism.

A rotatable and axially movable cylinder block 16 is mounted in the cavity 14 as by means of roller bearings 17 and 18 on the cylinder block at opposite ends thereof, the bearings being rotatable and axially slidable in outer bearing races 17a and 18a suitably secured respectively in the housing members 10 and 11 as by screws illustrated at 19 and 20. At one end, the cylinder block 16 is provided with a central bore having drive splines as at 24, and a drive member 25 rotatable in an end plate 25a has at one end a stub shaft portion 26 slidably splined in the cylinder block for rotation with the latter. The outer enlarged end of ,the drive member 25 .is hollow and is formed with internal splines as at 27 for connecting the drive member with a drive shaft or other coupling member as desired. It will be understood that when the device illustrated is utilized as a pump, the drive member 25 may be rotated by means of an independent prime mover coupled at '27, whereupon rotation of the drive member will effect rotation of the cylinderblock 16. Conversely, when the device is utilized as a motor, it will be understood that rotation of the cylinder block will result in driving the member 25 to in turn' drive a shaft or the like coupled at 27.

The cylinder block 16 is formed with two banks or rows of radial pump cylinders spaced axially along the block and designated generally by the reference numbers 30 and 31. Each row comprises a plurality (seven as illustrated) of radial cylinders 33 (FIGS. 2 and'4) extending inwardly from the outer periphery of the block along radial lines and angularly spaced equally about the block as seen best in FIG. 2. The two rows of cylinders include equal numbers of cylinders, with each of the cylinders in one row axially aligned in the block respectively with the cylinders in the other row, as best illustrated in FIG. 4.

Pumping pistons 34 are slidable in the cylinders 33, these being urged outwardly by the pressure of incoming fluid and by centrifugal force as thefcylinder block rotates, and being moved inwardly during rotation of the block by an eccentric means generally designated 35, which will be described in detail presently. I

Fluid passes to and from the pumping cylinders 33 through fluid intake-exhaust passages formed axially in the cylinder block and aligned respectively with the axially aligned pistons of the two rows 30 and 31. Eachintakeexhaust passage is formed by means of a first relatively large bore 37 leading from oneend (the left end as viewed in FIG. 4) of the cylinder block and intersecting the inner end of the associated cylinder 33 in the row 30 of cylinders. At the end of the bore 37, a smaller bore 38 continues axially of the cylinder block to intersect the inner end of the aligned cylinder 33 in therow 31. It will be understood that boressuch as that illustrated at 37 and 38 in FIG. 4 are provided for each pair 'of axially aligned cylinders, each of the seven bores 38 being visible in the sectional view of FIG. 2. With this arrangement, it will be understood that fluid may flow axially of the bores 37 and 38 into the cylinders 33 as the pistons 34 move outwardly, and may flow out from the cylinders through the bores 37 and 38 as the pistons 34 move inwardly of the block. The smaller bore 38 carries the flow' of the single row 31, while the larger bore 37 carries the flow of both rows of pistons.

Each of the bores 37 opens to the left end face of the cylinder block 16 for cooperation with intake and exhaust kidneys 40 and 41 (FIG. 3) disposed at diametrically opposite positions in a valve disk 42 having one face engaging the end face of the cylinder block. The intake and exhaust kidneys 40 and 41 are identical in size and shape with intake and exhaust kidneys 44 and 45 (FIGS. 3 and 5) formed in a port plate 46 secured in the housing member '10 as by screws illustrated at 47 in FIG. 4. The valve disk 42 includes a convex spherical face 49 which seats in a concave complementary spherical seat 50 in the port plate 46. Opposite the concave spherical surface 50, the kidneys 44 and 45 in the port plate 46 open into enlarged chambers as at 52 and'53 formed in the opposite face of the port plate and in register respectively with intake and exhaust passages 55 and 56 in the housing member 10 each having a threaded mouth as at 55a and 56a for receiving a suitable conduit coupling. The valve disk 42 is held against rotation with the cylinder block by means of a pin 58 (FIG. 4) fixed in the port plate 46 and loosely fitted in a recess as at 58a (FIG. 4) in the valve disk 42 whereby the disk is held against rotation but is free for limited universal movement by virtue of the spherical face 49 thereof in the spherical seat 50 which enables a self-aligning movement of the valve disk to conform to the end face of the cylinder block. This self-alignment feature compensates for any eccentricities, misalignment, or out of squareness due to temperature changes occurring under various conditions of operation or due to manufacturing imperfections in the cylinderblock or valve disk or in their mounting means and is claimed in the copending application of Donald B. Reinke, filed January 9, 1959, as Serial No. 785,910, now abandoned.

With the construction thus far described, it will be p of the cylinder block. Accordingly, in order to accomunderstood that as the cylinder block rotates the intakeexhaust passages 37, 38 leading to and from the pumping cylinders 33 successively communicate alternately with the intake and exhaust kidneys 40 and 41 in the valve disk 42'. As these kidneys communicate respectively with the kidneys 44 and 45 which in turn register with intake and exhaust passages 55 and 56, it will be understood that when'the latter passages are suitably connected with asource of fluid and a device to be supplied with pressure fluid, a complete pumping circuit is provided, While the device illustrated is usually referred to herein as a' pump, it will be understood that it is also operative as a motor by supplying fluid under pressure throughthe intake passage'si ior effecting rotation of the cylinder block. The passage 40, 44, 52, 55,0r the passage 41, 45, 53, 56 may either be described as an intake and the' other as an exhaust passage depending upon the direction of rotation imparted to or desired of the cylinder block 16.

Stroking of the pump pistons 34 inwardly of the cylinder block is effected by means of an eccentric previously designated generally by the reference number 35-. As seen best in FIGS. 2, 3 and 4, the eccentric 35 comprises an outer ring, or bearing race 60 having an enlargement 61 at the left side thereof (as viewed in FIG. 2), the enlargement being pivotally mounted as by a pivot pin means 62 which enables pivotal movement of the outer ring 60 about the axis of the pin 62, upwardly and downwardly as viewed in FIG. 2, from a maximum stroke position illustrated in FIG. 2 to a no-sn'oke position wherein the outer ring 60 would be positioned concentri- 'cally relative to the cylinder block.

The outer ring or race 60 rotatably and axially slidably supports roller bearings as at 64 on an inner ring or 'race 65. The inner ring 65 is formed with a pair of modate the peak 70, the outer surface of the cylinder block is reduced centrally of its length as at 71 in order to enable movement of the inner eccentric ring 65 and the inner peak 70 to maximum displacement positions.

The configuration of the inner eccentric surfaces 63 and 69 is utilized to maintain the inner eccentric. ring or race 65 centered axially relative to the two rows of pistons 30 and 31, More particularly, so long as the ring 65 is centered axially between the two rows of pistons, as illustrated in detail in FIG. 6, each row of pistons exerts outwardly directedforces as indicated by arrows 68a'and 69a having components both radial and axial of the eccentric ring, with the components of the two rows of pistons'being equal and opposite so that the ring remains in the centered position. In the event the ring moves axially in either direction from the central position illustrated, as for example toward the left .to the position illustrated in FIG. 7, the axial components of the two rows of pistons become unequal, as indicated by arrows 68b and 69b, with one axial'component decreasing (as in the case of arrow 69b) and the other increasing (as in the case of arrow 68b) in directions which tend to restore the FIG. 7).

ring to the central neutral position (toward the right in The length of piston stroke, or in other words pump displacement, may be varied by varying the pivotal position of the eccentric 35 about the pivot axis 62. This pivotal adjustment may be effected automatically under control of a piston 73 urged by a spring 74 toward an abutment 75 on the outer ring 60, thereby to urge the abutment and in turn the entire eccentric structure downwardly (FIG. 2) toward a maximum stroke position. The biasof the piston and the spring 74 is opposed by means of a universal pin 77 acting against the'underside of abutment 75 and urged upwardly as by means of a piston 78 slidable in a chamber 7 9 adapted to receive fluid I under pressure through an inlet (not illustrated) whereby 40, 41, etc., is enabled'due'to a pressure balancingof the cylinder block 16 which is provided bymeans' including a' plurality of axially extending cylinders 86 (FIG, 4) opening to the right end of the cylinder block 16 as viewed in FIGS. 3 and 4, such cylinders being aligned respecexcess of that of the spherical outer piston ends 34a. For

example, in a preferred embodiment of the pump, the surfaces 68 and 69 are formed on a radius of .750 inch, with a center located axially just beyond the ends of the eccentric, and the spherical outer piston ends have a radius of .500 inch. By this construction, it will be understood that due to the pivotal mounting at 62, the inner eccentric ring 65 may be moved from a concentric position to eccentric positions relative to the cylinder block so that engagement of the inner eccentric surfaces 68 and 69 with the outer piston ends, will effect a stroking of the pistons inwardly of the cylinder block as the latter rotates.

tively with the axially aligned pistons 34 of the two rows 30 and 31. The cylinders86 have pistons 87 slidable therein,'and urged outwardly of the cylinders as by means of individual springs 88 seated in the cylinders and hearing at opposite ends against the cylinder block and the pistons. The outer ends of the pistons 87 are provided with concave seats which piyotably receive the ball joints of bearing slippers 89 having end faces engaging a bearing plate 90 suitablytsecured in the housing member 11 as by means of'a pin 92 (FIG. 4).

The end face of each slipper 89 engaging the bearing plate 90- is formed with a cavity providing a pressure chamber as at 94 connected bya passage 95 through the slipper, a passage 96 through the balance piston 87, the hollow interior of the balance piston, the cylinder '86, and a passage 97 in the cylinder block communicating with the bore 38 which forms the intake-exhaust passage to the cylinders in the row 31. It will be understood that the balance pistons 86 correspond in number with the seven pistons in each bank of pistons, that the balance pistons are axially aligned respectively with the pistons in the two rows, and that the chambers 94in each of the bearing slippers 89 is connected respectively --with the aligned pumping pistons. In this fashion, the pressure fluid prevailing in each of the intakeexhaust passages 37, 38 is admitted to' the aligned pressure balance chamber' 94 so that the pressureof fiuid in the chambers 94, together with the springs 88, function to offset and coun terbalance the pressure of fluid exerted on the opposite end of the cylinder block through the kidneys 49 and 41. It will be understood that the arrangement is such that high pressure fluid acting through the high pressure kidney of the two kidneys 4t} and 41 against the left end of the cylinder block is opposed by high pressure fluid in chambers 94 of one or more balance slippers $9 which happen to be aligned with the high pressure kidney at the time, while in similar fashion the pressure of low pressure fluid in the low pressure kidney at the left end of the cylinder block is opposed by low pressure fluid in one or more of the chambers 94 which are at the time aligned with the low pressure kidney.

The counterbalanced cylinder block construction provided by the balance pistons 87 enables the use of axial porting as illustrated at 37, 38, 49, 41, rather than radial porting leading to the radial cylinders as by means of passages through a central pintle or hollow shaft construction, the axial porting illustrated being a preferred construction due to the simplicity and economy of manufacture, as well as the advantages of a more eficient operation. This feature is claimed in the copending application of Donald B. Reinke, filed January 7, 1959, as Serial No. 785,503.

With the curved surfaces 68 and 69 of the eccentric inner race, the axial forces normally acting on the inner race, due to the contact of the pistons with the curved inner surfaces, are such that the inner race will be centrally located between the two piston row. If one piston should become stuck down in its bore, the axial forces acting on the inner race will be less for that piston row having the stuck piston. As a result, the inner race moves toward such row of pistons, and as will be understood on viewing FIG. 7 each piston in this row exerts an increased axial component of force while each piston in the other row exerts a decreased axial component of force, so that the net forces acting on the eccentric inner race will reach an equilibrium with the inner race contacting both piston rows, but shifted slightly 0E center toward the row having the stuck piston.

I claim:

1. in a radial piston pump or motor device, a rotatable cylinder block having at least two axially spaced rows of radial cylinders therein, pistons reciprocable in the cylinders, an axially movable eccentric ring surrounding the cylinder block and having a pair of oppositely inclined concavely curved inner annular surfaces one engaging the outer ends of the pistons in one row, and the other engaging the outer ends of the pistons of the other row, said surfaces being disposed so that the axial components of the forces of the pistons against the surfaces normally tend to maintain the ring centered axially relative to the two rows of pistons and tend to return the ring to the axially centered position when it becomes axially displaced.

2. The combination of claim 1, wherein said eccentric surfaces are inclined longitudinally away from each other and radially outwardly of the ring.

3. The combination of claim 1, wherein the pistons have rounded outer end surfaces engaging said eccentric surfaces.

4. In a radial piston pump, a rotatable and axially movable cylinder block having two axially spaced rows of radial cylinders therein, pistons reciprocable in the cylinders, valving for admitting fluid to and exhausting fluid from the cylinders as the block rotates, an axially movable eccentric ring surrounding the block and having a pair of similar axially adjacent, oppositely inclined, axially concavely curved inner annular surfaces, one engaging the outer ends of the pistons in one row and the other engaging the outer ends of the pistons in the other row, said surfaces being disposed so that the axial components of the forces of the pistons in one row against the associated surface are equal to the axial components of the forces of the pistons in the other row against the associated surface when the ring is axially centered relative to the two rows of pistons, and so that when the ring is axially displaced toward one row of pistons the axial components of the forces of the pistons in one row are increased relative to the axial components of the forces of the other row to thereby tend to return the ring toward the centered position and to maintain the same in a position in which the axial forces reach an equilibrium.

5. The combination of claim 4, wherein the pistons have rounded outer end surfaces engaging said eccentric surfaces.

6. The combination of claim 4, wherein said eccentric surfaces are inclined axially away from each other and radially outwardly of the ring.

7. The combination of claim 4, wherein said eccentric surfaces are arcuately curved.

8. The combination of claim 4, wherein said eccentric surfaces are arcuately curved, axially of the ring and the outer ends of said pistons are spherical.

9. The combination of claim 8, wherein the radius of axial curvature of said eccentric surfaces is greater than the radius of said spherical piston ends.

10. In a radial piston pump, a pump housing, a cylinder block rotatable and axially movable in the housing, said block having two axially spaced rows of radial cylinders therein, pistons reciprocable in the cylinders, intake and exhaust passages communicating respectively with said cylinders and opening to one end of the block, a valve plate engaging said one end of the block and having intake and exhaust kidneys communicable successively with said intake and exhaust passages as the block rotates, thereby to admit and exhaust fluid from the cylinders, means yieldably urging the cylinder block toward the port plate, an eccentric surrounding the cylinder block comprising an outer ring pivotally mounted in the housing for adjustment to vary the piston stroke, an inner ring, and roller bearings mounting the inner ring rotatably and axially slidably in the outer ring, said inner ring having a pair of axially spaced, axially curved inner annular surfaces, one engaging the outer ends of the pistons in one row and the other engaging the outer ends of the pistons in the other row, said inner ring surfaces being oppositely inclined axially away from each other and radially outwardly of the ring and being arcuately concavely curved, and said pistons having spherical outer end surfaces, thereby to maintain the inner ring centered aidally relative to the two rows of pistons.

References Cited in the fi e of this patent UNITED STATES PATENTS 2,262,593 Thomas et al Nov. 11, 1941 2,458,985 Ferris et al Jan. 11, 1949 2,608,933 Ferris Sept. 2, 1952 2,629,736 Overbeke Dec. 9, 1952 FOREIGN PATENTS 1,132,654 France Nov. 5, 1956 

